FDA Approves Fedratinib for Forms of Myelofibrosis

The once-daily capsule therapy is the first drug indicated for the rare disease since ruxolitinib in 2011.

The US Food and Drug Administration (FDA) has approved fedratinib (Inrebic) capsules for the treatment of adult patients with particular forms of myelofibrosis.

Myelofibrosis—the chronic rare condition characterized by the formation of scar tissue on the bone marrow and the eventual enlargement of organs—previously had just 1 FDA-approved therapy in ruxolitinib (Jakafi). The approval of fedratinib breaks an eight-year spell of new marketing indications for the disease.

Fedratinib, from Impact Biomedicines, is indicated for the treatment of adults with intermediate-2, or high-risk primary or secondary myelofibrosis. Its approval was based on the results of a clinical trial comparing 2 different therapy doses (400 mg, 500 mg daily) to placebo in 289 randomized patients.

Trial results showed 35 of 96 (36.5%) patients treated with 400 mg fedratinib daily—the recommended dose per its label—experienced a significant therapeutic effect as per reduction of ≥35% in spleen volume from baseline to week 24.

A total of 36 patients treated with fedratinib reported a reduction of ≥50% in myelofibrosis-related symptoms including night sweats, itching, abdominal discomfort, pain under ribs on their left side, and pain in the bone and muscles, among others.

Fedratinib’s prescribing information will include a Boxed Warning advising healthcare professionals and patients on the risk of serious and even fatal encephalopathy associated with the drug. Physicians are advised to monitor patient thiamine levels prior to prescribing the therapy.

The therapy was originally granted Orphan Drug designation by the FDA for its benefit in a rare disease. In a statement regarding the approval, Richard Pazdur, MD, director of the FDA’s Oncology Center of Excellence and acting director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research, highlighted its addition to a very limited market.

"The FDA is committed to encouraging the development of treatments for patients with rare diseases and providing alternative options, as not all patients respond in the same way,” Pazdur said.